Multimodal abrading device for fusing a sacroiliac joint

ABSTRACT

A multimodal abrading device for preparing a sacroiliac joint (“SI Joint”) to receive a graft implant. The abrading device comprises an abrading head having abrading surfaces on a first pair of opposing sides, the abrading surfaces configured for decorticating the cortical bone of the SI Joint. The abrading head further comprises an open tip having a cutting edge configured to cut bone tissue in the SI Joint. The abrading device further comprises a slide hammer assembly at a proximal end of the abrading device, the slide hammer assembly having a released position that enables operation of the slide hammer assembly, and a locked position that prohibits operation of the slide hammer assembly.

CROSS-REFERENCE TO RELATED APPLICATION

Pursuant to 35 U.S.C. §§ 119(e) and 120, this application:

-   -   (i) is a continuation-in-part of U.S. patent application Ser.        No. 16/851,840, filed on Apr. 17, 2020, which claims the benefit        of U.S. Provisional Patent Application Ser. No. 62/910,913,        filed on Oct. 4, 2019; and    -   (ii) claims the benefit of U.S. Provisional Patent Application        Ser. No. 62/910,913, filed on Oct. 4, 2019,        the entire contents of each of which are incorporated herein by        this reference.

BACKGROUND (1) Field of Endeavor

The present invention relates generally to the field of sacroiliac jointfusion procedures, and more particularly, to a unique abrading devicefor preparing the sacroiliac joint for receiving a graft implant.

(2) Description of Related Art

The sacroiliac joint (“SI Joint”) is located at the interface betweenthe sacrum and ilium bones in a human's pelvic area. The SI Jointincludes strong ligaments that permit only slight movement between thesacrum and the ilium. The sacrum is connected to the base of the spine,and each ilium is connected to the top of the leg and hip area. Thus,the SI Joint is the interface between a human's upper body and lowerbody.

Dysfunction in the SI Joint is a common problem of back pain. In fact,over 25% of back pain is caused by SI Joint dysfunction. Even a properlyfunctioning SI Joint can become painful after certain types of spinalprocedures. For example, over 75% of lumbar fusion surgeries lead to SIJoint pain. Often, SI Joint pain or dysfunction is addressed by fusingthe SI Joint, and many past procedures exist for doing so. Past SI Jointfusion procedures involve installation of complex implant devices, suchas bone anchors, fusion devices, and multi-component implants. Theseprocedures involve complex devices, such as drills and drill bits, andmulti-component dilators, braces, and anchor installation devices. As aresult, fusion procedures using these devices are complex and timeconsuming, often leading to suboptimal results.

The present set of instruments seeks to overcome these problems byproviding a streamlined system and procedure for installing an allograftimplant in the SI Joint, without using a drill, drill bits, or otherrotary cutting instruments.

Another complication of SI Joint fusion is that promoting bone fusionoften involves decorticating the cortical bone inside the SI Joint. Thisdecortication is accomplished with a broach, a rasp, or a similarabrading device. These abrading devices often become lodged inside theSI Joint during the decortication process. When the abrading devicebecomes lodged, counter pressure cannot be applied to the patient tocounteract the pull-out force needed to dislodge the abrading device.Any such counter pressure applied to the patient could result in injuryto the patient or damage to the tissue surrounding the surgical site. Apast solution is to attach a separate slap hammer, or slide hammer, tothe abrading device such that pull-out forces can be applied to theabrading device without the need for applying any counter pressure tothe patient or to any other object. However, past slide hammerassemblies are cumbersome to operate, difficult to attach to theabrading device, and difficult to operate. They also complicate theinstrumentation needed to perform the SI Joint fusion procedure.

The present set of instruments seeks to overcome these problems byproviding a slide hammer integrated into the abrading device in a singletool.

SUMMARY OF THE PREFERRED EMBODIMENTS

In the preferred embodiment, the system and instrumentation describedherein comprises a working channel, a joint locator, an abrading device,and an implant inserter. The working channel has an insertion end and aworking end, and a channel extending therebetween. The working channelprovides a working passage for insertion of the other instruments of thesystem, and for delivery of the implant to the SI Joint. The insertionend has a pair of arms for providing engagement of the SI Joint anddistraction of tissue surrounding the insertion end. The insertion endfurther comprises a first iliac contour and a first sacral contour, bothof which are defined by the contour between the insertion arms and thebody of the working channel. The inside surface of the working channelhas an alignment means comprising a groove, recess, channel, indent, orthe like for receiving and engaging a ridge, rib, detent, or otherprotrusion on the mating instrument that is keyed to the alignmentmeans. In one embodiment, the working channel further comprises achannel collar for receiving mating components of the joint locator,abrading device, or implant inserter in an abutting engagement.

The joint locator has an insertion end and a handle. The insertion endcomprises a penetration tip for penetrating the soft tissue in proximityto the SI Joint. A leading edge of the penetration tip may comprise, inwhole or in part, a blade or chisel component to promote thispenetration. Alternately, the penetration tip may be rounded or dull sothat it does not inadvertently penetrate the sacrum or ilium in theevent that the joint locator is misaligned during insertion. The jointlocator insertion end comprises a second iliac contour and a secondsacral contour. The outside surface of the joint locator has a keyingmeans for engagement with the alignment means of the working channel,the keying means comprising a ridge, rib, detent, or other protrusion onthe outside surface of the joint locator capable of engaging thealignment means.

The abrading device comprises a hammer sleeve at a proximate end, anabrading head at a distal end, and a keying means that is similar to thejoint locator keying means of the joint locator. In the preferredembodiment, the abrading device further comprises a slap hammerassembly, or slide hammer assembly. In one embodiment, the slide hammerassembly comprises a base connected to a shaft, and a releasing meansthat releasably connects a hammer sleeve to the base. The releasedhammer sleeve is configured for sliding engagement along the shaft. Tooperate the slide hammer assembly, the hammer sleeve is disengaged fromthe base, placing the slide hammer assembly in its released position.This released position enables the hammer sleeve to slide freely alongthe shaft. The hammer sleeve is pulled until a diaphragm inside thehammer sleeve engages a stop end of the shaft, thereby causing an impactthat delivers the slide hammer force.

The implant inserter comprises a handle and an implant insertion end.The implant insertion end has a pair of tines for holding the implantduring the process of inserting the implant into the SI Joint. Theimplant inserter further comprises an inserter keying means, which issimilar to the keying means of the joint locator.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the posterior view of a typical human pelvis.

FIG. 2 is a perspective view of an embodiment of an allograft implantfor insertion into the SI Joint.

FIG. 3 shows an alternate view of one embodiment of an allograftimplant.

FIG. 4 shows an embodiment of the instruments in the joint fusionapparatus.

FIG. 5 shows an embodiment of the working channel and an embodiment ofthe joint locator.

FIG. 6 shows a close up of the insertion end of one embodiment of aworking channel.

FIG. 7 shows an alternate view of the embodiment shown in FIG. 6.

FIG. 8 is an enlarged view of the insertion end of an embodiment of thejoint locator fully inserted into the working channel of FIG. 4.

FIG. 9 is an enlarged view showing the device of FIG. 8 with theorientation reversed.

FIG. 10 shows a close up of the working end of one embodiment of aworking channel.

FIG. 11 shows the joint locator of FIG. 4 partially inserted into theworking channel.

FIG. 12 shows the joint locator of FIG. 4 fully inserted into theworking channel.

FIG. 13 shows the working channel of FIG. 4 and an embodiment of theabrading device.

FIG. 14 is an enlarged view of an embodiment of the abrading head.

FIG. 15 shows an enlarged view of one embodiment of an abrading head.

FIG. 16 shows the abrading device of FIG. 13 with an embodiment of aslide hammer disassembled.

FIG. 17 is an enlarged view of an embodiment of the connection interfaceof a slide hammer.

FIG. 18 shows a close up of one embodiment of the diaphragm and threadedconnector of a slide hammer assembly.

FIG. 19 shows the abrading device of FIG. 13 partially inserted into theworking channel of FIG. 4.

FIG. 20 shows the abrading device of FIG. 13 fully inserted into theworking channel of FIG. 4 with the slide hammer in its locked position.

FIG. 21 shows the abrading device of FIG. 13 fully inserted into theworking channel of FIG. 4 with the slide hammer in its extendedposition.

FIG. 22 shows the working channel of FIG. 4 and an embodiment of theinsertion device.

FIG. 23 is an enlarged view of the insertion end of the insertion deviceof FIG. 22.

FIG. 24 shows the insertion device of FIG. 22 with an embodiment of anallograft implant loaded into the tines of the insertion end.

FIG. 25 shows the insertion device of FIG. 22 and the allograft implantpartially inserted into the working channel of FIG. 4.

FIG. 26 shows the insertion device of FIG. 22 and the allograft implantfully inserted into the working channel of FIG. 4.

FIG. 27 is a front view of one embodiment of the incision guide.

FIG. 28 is a top view of one embodiment of the incision guide

FIG. 29 is a right side view of one embodiment of the incision guide.

FIG. 30 is a cross-sectional view A-A of the incision guide of FIG. 29.

FIG. 31 is an isometric view of one embodiment of the incision guide.

FIG. 32 is a side view of one embodiment of an allograft implant.

FIG. 33 is a cross-sectional view B-B of the allograft implant of FIG.32.

FIG. 34 is a top view of one embodiment of an allograft implant.

FIG. 35 is a rear view of one embodiment of an allograft implant.

FIG. 36 is a front view of one embodiment of an allograft implant.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the drawings, the system and instrumentation forfusing a sacroiliac joint (“SI Joint”) and the corresponding multimodalabrading device will now be described with regard for the best mode andthe preferred embodiment. The embodiments disclosed herein are meant forillustration and not limitation of the invention. An ordinarypractitioner will appreciate that it is possible to create manyvariations of the following embodiments without undue experimentation.

The system and instrumentation described herein are used primarily forfusing an SI Joint 3 in the pelvis of a human. Referring to FIGS. 1-3,an allograft implant 5 is placed in the soft tissue of the SI Joint 3between the sacrum 1 and the ilium 2 of the pelvis. For the purpose ofreference, the SI Joint plane as used herein means the general plane ofthe SI Joint 3 as defined by the abutting surfaces of the sacrum 1 andilium 2. The implant 5 provides a matrix for bone healing across the SIJoint, thereby fusing the sacrum 1 and ilium 2 together. In oneembodiment, the implant 5 generally comprises a nose 6 and at least onepair of opposing lateral sides 7, each comprising a groove 8 that isdisposed at least partially along the length of each such lateral side7.

Referring to FIG. 4, in one embodiment, the system comprises a workingchannel 10, a joint locator 20, an abrading device 30, and an implantinserter 60. Each of these instruments has a longitudinal axis along thecenterline of its length. Referring to FIG. 5, the working channel 10 isa tube-like member that provides a working passage for insertion of theother instruments of the system, and for delivery of the implant 5 tothe SI Joint 3. The working channel 10 is a cannula, a lumen, a sleeve,or another device suitable for providing working access of the otherinstruments to the SI Joint 3, as described below. The working channel10 has an insertion end 11 and a working end 12, and a channel 13extending therebetween. The channel 13 is a tube or bore having a crosssection that is rectilinear or curvilinear. The insertion end 11 has apair of arms 14 for providing engagement of the SI Joint 3 anddistraction of tissue surrounding the insertion end 11. The arms 14 areprobes, prongs, or other members protruding from the insertion end 11 ofthe working channel 10. Insertion of the arms 14 into the SI Joint 3, asdescribed below, resists or prevents the working channel 10 fromrotating about its longitudinal axis in relation to the SI Joint 3. Thelongitudinal axis generally extends along the length of the workingchannel 10 in proximity to the centerline of the channel 13.

The insertion end 11 of the working channel 10 is configured for seatingin and against the SI Joint 3, and against the sacrum 1 and ilium 2 inparticular. The insertion end 11 comprises a first iliac contour 15 anda first sacral contour 16, both of which are defined by the contourbetween the insertion arms 14 and the body of the working channel 10.For example, referring to FIGS. 6-9, one side of the insertion end 11comprises the arms 14 connected to the working channel 10 via the firstiliac contour 15, which is configured for abutment against the ilium 2when the arms 14 are inserted into, and seated within, the SI Joint 3 asdescribed below. The opposite side of the insertion end 11 comprises thearms 14 connected to the working channel 10 via the first sacral contour16, which is configured for abutment against the sacrum 1 when the arms14 are inserted into, and seated within, the SI Joint 3.

Referring to FIGS. 5 and 10, the inside surface of the working channel10 has a means for aligning instruments, the alignment means 17comprising a groove, recess, channel, indent, or the like for receivingand engaging a ridge, rib, detent, or other protrusion on the matinginstrument that is keyed to the alignment means 17. In one embodiment,the working channel 10 further comprises a channel collar 18 forreceiving mating components of the joint locator 20, abrading device 30,or implant inserter 60 in an abutting engagement, as described below. Inan embodiment of the channel collar 18, the collar further comprises analignment means 17.

Referring to FIG. 5, the joint locator 20 has an insertion end 21 and ahandle 22, or working end. The insertion end 21 comprises a penetrationtip 23 for penetrating the soft tissue in proximity to the SI Joint 3.This soft tissue is the soft tissue between the surface of the patient'sskin the SI Joint 3, such as muscle tissue, and the soft tissue insidethe SI Joint 3, such as cartilage and ligaments. The penetration tip 23is configured for penetrating these types of soft tissue. For example,one embodiment of the penetration tip 23 comprises a blade or chiselcomponent for cutting the soft tissue. A leading edge of the penetrationtip 23 may comprise, in whole or in part, such a blade or chiselcomponent. In another embodiment of the penetration tip 23, thepenetration tip 23 is rounded or dull so that it does not inadvertentlypenetrate the sacrum 1, the ilium 2, or any other bone structure in thepelvic area in the event that the joint locator 20 is misaligned duringinsertion and penetration. In this embodiment, the penetration tip 23tends to tear or rip through the soft tissue rather than slicing orcutting through it.

Referring again to FIGS. 8 and 9, the joint locator 20 insertion end 21comprises a second iliac contour 24 and a second sacral contour 25. Forexample, one side of the joint locator 20 insertion end 21 comprises thesecond iliac contour 24, which is configured for abutment against theilium 2 when the penetration tip 23 is inserted into the SI Joint 3, asdescribed below. The other side of the joint locator 20 insertion end 21comprises the second sacral contour 25, which is configured for abutmentagainst the sacrum 1 when the penetration tip 23 is inserted into the SIJoint 3.

The outside surface of the joint locator 20 has a means for keying withthe alignment means 17 of the working channel 10, the keying means 27comprising a ridge, rib, detent, or other protrusion on the outsidesurface of the joint locator 20 capable of engaging the alignment means17 to resist or prevent relative rotation between the joint locator 20and the working channel 10.

In one embodiment, referring to FIGS. 5, 11, and 12, the joint locator20 has a channel 26 for receiving the K-wire 4. This channel 26 is acannula, lumen, or other bore-like feature capable of receiving theK-wire 4 in a pass-through manner, preferably along a longitudinal axis,or centerline, of the joint locator 20. In one embodiment of the jointlocator 20, the handle 22 further comprises a stop 28 for abuttingagainst the channel collar 18 of the working channel 10.

Referring to FIG. 13, the abrading device 30 comprises a hammer sleeve31 at a proximate end and an abrading head 32 at a distal end. Theabrading head 32 is a rasp, broach, or other abrading tool that is usedto grate, abrade, or otherwise decorticate the cortical bone inside theSI Joint 3. In one embodiment, shown in FIGS. 14 and 15, the abradinghead 32 is a generally rectangular member comprising abrading surfaces33 on a first pair of opposing sides of the head 32, an open tip 34 forinsertion into the SI Joint 3, and a second pair of opposing sides 35between the abrading surfaces 33, the second pair of opposing lateralsides 35 having one or more lateral openings. Each abrading surface 33comprises one or more teeth, barbs, blades, ridges, slots, broaches, orother members or features capable of abrading the cortical bone in theSI Joint 3. The open tip 34 comprises a cutting edge 36 around all orpart of the leading edge of the open tip 34, the cutting edge 36configured for cutting bone tissue inside the SI Joint 3, such as thesacrum 1 or ilium 2. The abrading surfaces 33 and lateral sides 35 forma box-like abrading head 32 having a void therein. The openings in thelateral sides 35 enable lateral ingress into and egress from the void.For example, as the cutting edge 36 cuts bone tissue inside the SI Joint3, the dislodged bone tissue falls into the void and may exit theabrading head 32 via the openings in the lateral sides 35.

In one embodiment, each side of the first pair of opposing sides is asubstantially planar member having a distal edge terminating at the opentip 34, the interface between the open tip 34 and the distal edgecomprising a substantially straight cutting edge 36. Each side of thesecond pair of opposing sides may comprise a curved distal portionterminating at the open tip 34, the interface between the open tip 34and the curved distal portion comprising a curved cutting edge 36. Thecurved distal portion of each side of the second pair of opposing sides35 may further comprise a taper toward its opposite side of the secondpair of opposing sides 35.

Referring to FIG. 19, the abrading device 30 further comprises a keyingmeans 37, which is similar to the joint locator 20 keying means 27described above. The keying means 37 mates with the alignment means 17in the working channel 10 to resist or to prevent relative rotationbetween the abrading device 30 and the working channel 10 about eachmember's respective longitudinal axis. The abrading device 30 furthercomprises an abrading stop 38 for abutting against the channel collar 18of the working channel 10. In one embodiment, the abrading device 30further comprises a K-wire channel for receiving the K-wire 4. ThisK-wire channel is a cannula, lumen, or other bore-like feature capableof receiving the K-wire 4 in a pass-through manner, preferably along alongitudinal axis of the abrading device 30.

Referring to FIGS. 16, 17, and 18, the abrading device 30 furthercomprises a slap hammer assembly, or slide hammer assembly 40. In oneembodiment, the slide hammer assembly 40 comprises a base 51 connectedto a shaft 44, and a releasing means that releasably connects a hammersleeve 31 to the base 51. The released hammer sleeve 31 is configuredfor sliding engagement along the shaft 44. The releasing means is anymeans for releasably connecting the hammer sleeve 31 to the base 51,thereby transitioning the slide hammer assembly between its releasedposition and its locked position. The releasing means could be a matingthreaded connection, a quick disconnect attachment, a depressible tab, alatch, a clasp, a clip, a clamp, or other equivalent connectionstructure.

In one embodiment, shown in FIGS. 16, 17, and 18, the releasing means isa mating threaded connection. This embodiment includes a collar 41 onthe abrading device 30, a slide hammer shaft 44, and the hammer sleeve31. The collar 41 comprises internal threads 42 and external threads 43.The shaft 44 comprises a threaded end 45 and a stop end 46. The hammersleeve 31 has a threaded connector 48 and a hollow, cylindrical borecomprising an internal diaphragm 47 having a diaphragm opening 49 (seeFIG. 18). The diaphragm opening 49 is sized to permit sliding passage ofall parts of the shaft 44 except the stop end 46. The stop end 46 issized too large to fit through the diaphragm opening 49.

To assemble the slide hammer assembly 40 of this embodiment, thethreaded end 45 of the shaft 44 is inserted into the bore of the hammersleeve 31, through the diaphragm 47 inside the hammer sleeve 31, and thethreaded end 45 is threaded into, and mated with, the internal threads42 of the collar 41. The threaded connector 48 in the hammer sleeve 31is then mated to the external threads 43 on the collar 41 to promote asecure connection. The stop end 46 is disposed inside the bore of thehammer sleeve 31 on a side of the diaphragm 47 opposite that of thelocation of the threaded connector 48. In this configuration, shown inFIG. 20, the slide hammer assembly 40 is in its locked position.

To operate the slide hammer assembly 40, the threaded connector 48 isdisengaged from the external threads 43 of the collar 41, placing theslide hammer assembly 40 in its released position, which is shown inFIG. 21. This released position enables the hammer sleeve 31 to slidefreely along the shaft 44. The hammer sleeve 31 is pulled until thediaphragm 47 inside the hammer sleeve 31 engages the stop end 46 of theshaft 44, thereby causing an impact that delivers the slide hammerforce. Thus, the slide hammer assembly has a released position thatenables operation of the slide hammer assembly, and a locked positionthat prohibits operation of the slide hammer assembly.

Referring to FIGS. 22-26, the implant inserter 60 comprises a handle 61and an implant insertion end 62. The implant insertion end 62 has a pairof tines 63 for holding the implant 5 during the process of insertingthe implant 5 into the SI Joint 3. Each tine 63 is supported by a tineshaft 66, which terminates at a shoulder 67. The tine shafts 66 provideflexibility such that the implant 5 is removably retained between thetines 63 with the shoulder 67 abutting against the implant 5 (see FIG.24). For example, in one embodiment the width of the implant 5 betweenthe opposing grooves 8 is slightly larger than the space between therespective tines 63 such that when the implant 5 is seated in theimplant insertion end 62, the respective tines 63 are pushed slightlyapart by the grooves 8. This causes a slight amount of friction betweenthe tines 63 and the grooves 8, thereby releasably retaining the implant5 in the implant insertion end 62.

The implant inserter 60 further comprises an inserter keying means 65,which is similar to the keying means 27 of the joint locator 20. Theinserter keying means 65 mates with the alignment means 17 in theworking channel 10 to resist or to prevent relative rotation between theimplant inserter 60 and the working channel 10 about each member'slongitudinal axis. In one embodiment, the implant inserter 60 furthercomprises a channel 64 for receiving the K-wire 4 (see FIG. 23). Thischannel 64 is a cannula, lumen, or other bore-like feature capable ofreceiving the K-wire 4 in a pass-through manner. In one embodiment ofthe implant inserter 60, the handle 61 further comprises an inserterstop 68 for abutting against the channel collar 18 of the workingchannel 10.

In one embodiment of a method of installing the implant 5, the procedurefor installing the implant 5 in the SI Joint 3 is started by locating aninsertion point in the SI Joint 3, which is the location where theimplant 5 is to be installed. For example, the free end of the K-wire 4in inserted into the SI Joint 3 at the insertion point where the implant5 is to be installed, thereby defining an intended location for theimplant void. The implant void is a seat or groove between the sacrum 1and ilium 2 for seating the implant 5, as described below. The K-wire 4is preferably inserted from a posterior approach. It is preferable, butnot required, that the implant 5 is installed under the portion of theposterior superior iliac spine that overhangs the SI Joint 3. One ormore alternate location are also suitable for fusion of the SI Joint 3.A K-wire 4 is inserted into the SI Joint 3 at each location where animplant 5 is to be inserted.

In one embodiment, referring to FIGS. 27-31, the initial incision ismade using an incision guide 70 that comprises a channel 71 forremovably receiving a K-wire 4. The incision guide 10 further comprisesa guide slot 72 for receiving a blade, scalpel, or similar cuttinginstrument (not shown). The guide slot 72 is disposed at an angle inrelation to the channel 71 such that when the scalpel is extendedthrough the guide slot 72, the tip of the scalpel is disposed above thepatient's skin at the proper location for making the initial incisioninto the patient. This location is above the SI Joint 3 where theallograft implant 5 will be introduced into the soft tissue above the SIJoint 3, and eventually into the SI Joint 3 itself. In one embodiment,the guide slot 72 is oriented at an angle A of about 70° to about 75° inrelation to horizontal H (see FIG. 30). In this orientation, the channel71 is perpendicular to horizontal.

In this embodiment, the K-wire 4 is inserted into the SI Joint 3 asdescribed above. The incision guide 70 is placed over the K-wire 4 suchthat the K-wire 4 is slidably received into the channel 71. In oneembodiment, the scalpel is inserted into the guide slot 72 and retainedin fixed relation to the channel 71 such that the cutting tip of thescalpel is located in close proximity to the K-wire 4. The incisionguide 70 is then advanced toward the SI Joint 3, and the cutting tip ofthe scalpel makes the incision as the incision guide 70 advances. Oncethe initial incision is adequately formed, the incision guide 70 islifted to remove it from the K-wire 4, and the surgery proceeds withother instruments for inserting the implant 5 into the SI Joint 3.

The joint locator 20 is then fully inserted into the working channel 10(see FIG. 12). In mating the joint locator 20 inside the working channel10, the keying means 27 of the joint locator 20 is oriented to engagethe alignment means 17 of the working channel 10. This engagementenables the first iliac contour 15 of the working channel to be disposedin mating alignment with the second iliac contour 24 of the jointlocator 20, and the first sacral contour 16 of the working channel 10 tobe disposed in mating alignment with the second sacral contour 25 of thejoint locator 20 (see FIGS. 8 and 9). The respective first and secondiliac contours 15, 24 are configured to be seated in mating placementagainst the ilium 2 when the insertion end 11 is disposed inside the SIJoint 3, and the respective first and second sacral contours 16, 25 areconfigured to be seated in corresponding mating placement against thesacrum 1 when the insertion end 11 is disposed inside the SI Joint 3.The stop 28 abuts against the channel collar 18 of the working channel10 to prevent over penetration of the penetration tip 23 into the SIJoint 3, thereby avoiding damage to the soft tissue and nerves on theanterior side of the SI Joint 3.

The free end of the K-wire is inserted into the K-wire channel 26 of thecombined joint locator 20/working channel 10, and this combined deviceis advanced toward the SI Joint 3, guided by the K-wire 4. As the jointlocator 20/working channel 10 combination is advanced, the penetrationtip 23 cuts or tears though the soft tissue above and inside the SIJoint 3. If necessary, the combined joint locator 20/working channel 10is advanced via blows from a mallet against the proximal end of thehandle 22 to deliver an appropriate axial force. The impact from themallet causes an axial force that is transmitted though the handle 22 tothe stop 28, where the axial force is imparted to the channel collar 18and into the working channel 10. As such, the impact force from a malletis shared between the working channel insertion end 11 and the jointlocator insertion end 21.

The combined joint locator 20/working channel 10 is advanced until therespective first and second iliac contours 15, 24 abut the ilium 2 andthe respective first and second sacral contours 16, 25 abut the sacrum1. In this position, the arms 14 of the working channel 10 are disposedinside the SI Joint 3 to retain the proper alignment of the workingchannel 10, and therefore the alignment means 17, thereby ensuring aproper alignment of the abrading device 30 and the implant inserter 60later in the procedure. In some embodiments, insertion of the arms 14into the SI joint 3 will distract the joint, thus separating the sacrum1 and the ilium 2. This distraction establishes a uniform width of thespacing in the SI joint 3 prior to use of the other instrumentation.Thus, the instrumentation described herein will work with a patient ofany size because the arms 14 set the width of the SI joint 3 to auniform distance regardless of the size or scale of the sacrum 1 orilium 2.

In an alternate embodiment of the installation method, a K-wire 4 isomitted from the procedure. Instead, the combined joint locator20/working channel 10 is advanced through an incision in the patient,and this advancement continues as described above until the insertionends 11, 21 are inserted into the SI Joint 3 as described above.

Once the combined joint locator 20/working channel 10 device is properlyseated in the SI Joint 3, the joint locator 20 is removed from theworking channel 10. The surrounding soft tissue remains distracted ordilated by the working channel 10 and the respective arms 14, therebyenabling direct access to the SI Joint 3 area. The abrading device 30 isthen inserted into the working channel 10, with the keying means 37engaging the alignment means 17 to promote proper alignment of theabrading head 32 with respect to the SI Joint 3. The abrading head 32 isadvanced through the working channel 10 until the abrading head 32 makescontact with the SI Joint 3. The abrading head 32 is forced into the SIJoint 3 (using a mallet if necessary), and the cutting edge 36 cuts thebone tissue and any soft tissue, such as ligaments or cartilage. Theabrading stop 38 abuts against the channel collar 18 of the workingchannel 10 to prevent over penetration of the abrading head 32 into theSI Joint 3, thereby avoiding damage to the soft tissue and nerves on theanterior side of the SI Joint 3. During this process, the cutting edge36 cuts through the relevant bone portions of the sacrum 1 and ilium 2,and the abrading surfaces 33 works in connection with the cutting edge36 to decorticate the cortical bone inside the SI Joint 3, therebyforming a decorticated implant void at the insertion point of the SIJoint 3. The decorticated implant void has a generally rectangular crosssectional shape such that the decorticated implant void is adapted forreceiving the fusion implant 5, which has a generally rectangular crosssectional shape for mating with the decorticated implant void. Thus, useof the abrading head 32 enables installation of the implant 5 withoutthe need for using a drill or other rotary cutting instrument to form apilot hole for the implant 5. As used herein, a rotary cuttinginstrument is any device capable of cutting material by turning,rotating, or other angular motion about an axis of the device, whetherpower-driven or hand-driven. This is a significant improvement of thepresent set of instruments over prior art methods and instrument setsfor SI Joint 3 fusion.

The abrading device 30 is then worked in and out of the working channel10 such that the abrading surfaces 33 abrade, or decorticate, therespective surfaces of the sacrum 1 and the ilium 2 inside the SI Joint3. Again, the abrading stop 38 abuts against the channel collar 18 toprevent over penetration of the abrading head 32. During this process,the abrading head 32 may become lodged in the SI Joint 3, becomingdifficult to remove. In these instances, the slide hammer assembly 40 isenabled so that the abrading head 32 may be removed by the impact forceof the slide hammer assembly 40, as described above. Operation of theslide hammer assembly 40 provides a significant advantage over priorsystems because when the abrading head 32 becomes lodged in the SI joint3, counter pressure cannot be applied to the patient to counter thepull-out force needed to dislodge the abrading head 32 from the SI joint3. The slide hammer assembly 40 enables removal of a lodged abradinghead 32 in a safe manner without applying any counter pressure to thepatient.

As the abrading head 32 is worked in and out of the SI Joint 3, theabrading surfaces 33 abrade the cortical bone of the sacrum 1 and theilium 2 inside the SI Joint 3. The cortical bone is abraded untilbleeding begins, thereby promoting the patient's healing process of thecortical bone. This degree of abrasion and corresponding healingpromotes fusion of the SI Joint 3.

Once the SI Joint 3 is adequately abraded, the abrading device 30 isremoved from the working channel 10. Thus, this method of fusing the SIJoint 3 comprises steps for forming a void for a fusion implant 5 in theSI Joint 3 without using a rotary cutting instrument. At this point inthe procedure, the K-wire 4 may be removed from the working channel 10to enable proper advancement of the implant 5 through the workingchannel 10 and proper installation of the implant 5 into the SI Joint 5.Alternately, the K-wire 4 can be removed from the working channel 10 atany time after the working channel 10 is properly seated in the SI Joint3, as described above.

The allograft implant 5 is placed into the tines 63 of the implantinserter 60 such that each tine 63 is seated into a mating groove 8 onthe lateral side 7 of the implant 5, and the shoulder 67 abuts theimplant 5 (see FIG. 24). The implant inserter 60 is then inserted intothe working channel 10 such that the keying means 65 engages thealignment means 17 to ensure proper orientation of the implant inserter60, and thus, the implant 5. The implant inserter 60 is used to deliverthe implant 5 to the abraded area of the SI Joint 3 through the workingchannel 10. If necessary, the implant inserter 60 is struck by a malletto force the implant 5 into the abraded area of the SI Joint 3, theshoulder 67 transferring the impact force to the implant 5. In theseinstances, the inserter stop 68 abuts against the channel collar 18 ofthe working channel 10 to prevent over penetration of the implant 5 intothe SI Joint 3, thereby ensuring that the implant 5 is properly placedinside the SI Joint 3.

Once the implant 5 is fully inserted into the SI Joint 3, the implantinserter 60 is removed from the working channel 10, leaving the implant5 installed in the abraded area of the SI Joint 3. In most instances,the friction force between the implant 5 and the inside of the SI Joint3 is greater than the friction force between the respective tines 63 andgrooves 8. In these instances, removal of the implant inserter 60 isaccomplished by applying a removal force to the implant inserter 60greater than the friction force between the tines 63 and the grooves 8.The tines 63 slice out of the grooves 8 as the implant inserter 60 isretracted from the working channel 10. In other instances, the frictionforce between the implant 5 and the inside of the SI Joint 3 is lessthan the friction force between the respective tines 63 and grooves 8.In these instances, removal of the implant inserter 60 is accomplishedby inserting a K-wire 4 or similar device into the K-wire channel 64 andadvancing the K-wire 4 until the distal end of the K-wire abuts againstthe implant 5 between the tines 63. The K-wire 4 is used to hold theimplant 5 in place inside the SI Joint 3 as the removal force is appliedto the implant inserter 60. The tines 63 are thereby removed from thegrooves 8 as the K-wire 4 holds the implant 5 in its installed location.Once the tines 63 are pulled free from the grooves 8, the implantinserter 60 is disengaged from the implant 5, and the implant inserter60 and the K-wire 4 are removed from the working channel 10. The workingchannel 10 is then removed from the surgical site, causing the SI Joint3 to contract, thereby exerting a compressive force on the implant 5.This compressive force is caused by the ligaments of the SI Joint 3 thatcompress the joint, thereby holding it together. The surgical site isthen sterilized and closed for healing.

As the abraded cortical bone heals, the bone fuses with the allograftimplant 5, eventually causing the sacrum 1 and the ilium 2 to growtogether at the location of the implant 5, thereby fusing the SI Joint3.

In any of the foregoing embodiments, one or more instruments maycomprise disposable material, such as medical grade plastics, certainmetals, or other disposable material.

Referring to FIGS. 32-36, the implant 5 generally has two opposing faces81. When the implant 5 is inserted into the SI Joint 3, one opposingface 81 is disposed against the sacrum 2, and the other opposing face 81is disposed against the ilium 3. Each of the opposing faces 81 comprisesone or more anti-migration features 82, such as teeth or ridges, thatresist movement of the implant inside the SI Joint 3.

In one embodiment, the implant 5 comprises a body 83 having a proximalend 86, a distal end 87, and a length disposed therebetween, the distalend having a rounded nose 6. The body 83 further comprises two sides 7,each side 7 comprising a groove 8 beginning at the proximal end 86 ofthe body 83 and continuing along each of the two sides 7 for at leastpart of the length, the distance between the two sides 7 defining awidth W of the body.

The implant 5 further comprises a central graft window 85 that enablesfusion of the SI Joint 3 to occur through the implant 5. The graftwindow 85 is disposed between each of the opposing faces 81, the graftwindow 85 providing passage through the body 83 between the two opposingfaces 81. The portion of the body 83 located between the graft window 85and each of the sides 7 defines a wall 84.

When viewed in cross section (see FIG. 33), the area of the graft window85 is about 35% to about 40% of a first cross-sectional area of thebody, which is the area of the total implant 5 as shown by the hatchedarea in FIG. 33. The area of the window 85 is about 60% of the totalarea of each opposing face 81 that makes contact with the bone, whetherthe sacrum 1 or the ilium 2. These ratios provide a strength-to-contactarea relationship that optimizes performance of the implant 5 as apromoter of SI Joint 3 fusion. In these ratios, the implant 5 providesenough strength so that it is not crushed inside the SI Joint 3, and itprovides a large enough graft window 85 to expedite fusion of the SIJoint 3 across and through the implant 5.

In one embodiment, the graft window 85 has a proximal portion 88 locatedin proximity to the grooves 8, and a distal portion 89, the proximalportion 88 having a width W1 that is less than a width W2 of the distalportion 89 such that the wall 84 maintains a minimum thickness in arange of about 17% to about 20% of the width W of the body 83.

In the foregoing embodiments, it is preferable, but not required, thatthe graft window 85 is unobstructed by internal or intermediatesupports. Such internal or intermediate supports are sometimes used inallograft implants to provide structural support to the implant.However, these internal or intermediate supports obstruct bone fusionfrom occurring through the window. As such, the graft window 85 mayprovide an open passage through the body 83 between the opposing faces81. The open passage may be rectilinear or curvilinear. The proximal end86 of the body 83 may further comprise a taper 90 that reduces a secondcross-sectional area of the body 83.

The foregoing embodiments are merely representative of the SI Jointfusion instruments and multimodal abrading device, and these embodimentsare not meant for limitation of the invention. For example, personsskilled in the art would readily appreciate that there are severalembodiments and configurations of slide hammer devices, abradingsurfaces, and other features described herein that will notsubstantially alter the nature of the SI Joint fusion instruments andabrading device. As another example, the alignment means 17 and therespective keying means 27, 37, 67 could be reversed such that theworking channel 10 comprises a keying means, and the joint locator 20,rasp device 30, and implant inserter 60, respectively, comprise a matingalignment means. Consequently, it is understood that equivalents andsubstitutions for certain elements and components set forth above arepart of the invention described herein, and the true scope of theinvention is set forth in the claims below.

1. A multimodal abrading device for forming a fusion implant insertionlocation in a sacroiliac joint, the abrading device comprising: anabrading head at a distal end of the abrading device, the abrading headhaving: abrading surfaces on each of a first pair of opposing sides, theabrading surfaces comprising one or more teeth, barbs, blades, ridges,slots, broaches, or other members capable of abrading a cortical bone ofthe sacroiliac joint; and an open tip comprising a cutting edge disposedat a leading edge of the open tip, the cutting edge configured to cutbone tissue in the sacroiliac joint; and a slide hammer assembly at aproximal end of the abrading device, the slide hammer assembly having areleased position that enables operation of the slide hammer assembly,and a locked position that prohibits operation of the slide hammerassembly.
 2. The multimodal abrading device of claim 1, wherein theabrading head further comprises a void and a second pair of opposingsides, each of the second pair of opposing sides having an opening forenabling lateral ingress into and egress from the void.
 3. Themultimodal abrading device of claim 1, wherein each side of the firstpair of opposing sides is a substantially planar member having a distaledge terminating at the open tip, an interface between the open tip andthe distal edge comprising a substantially straight cutting edge.
 4. Themultimodal abrading device of claim 1, wherein the abrading head furthercomprises a void and a second pair of opposing sides, each side of thesecond pair of opposing sides comprising a curved distal portionterminating at the open tip, an interface between the open tip and thecurved distal portion comprising a curved cutting edge.
 5. Themultimodal abrading device of claim 2, wherein each side of the firstpair of opposing sides is a substantially planar member having a distaledge terminating at the open tip, an interface between the open tip andthe distal edge comprising a substantially straight cutting edge.
 6. Themultimodal abrading device of claim 5, wherein each side of the secondpair of opposing sides comprises a curved distal portion terminating atthe open tip, the interface between the open tip and the curved distalportion comprising a curved cutting edge.
 7. The multimodal abradingdevice of claim 4, wherein the curved distal portion of each side of thesecond pair of opposing sides comprises a taper toward its opposite sideof the second pair.
 8. The multimodal abrading device of claim 7,wherein each side of the first pair of opposing sides is a substantiallyplanar member having a distal edge terminating at the open tip, theinterface between the open tip and the distal edge comprising asubstantially straight cutting edge.
 9. A multimodal abrading device forforming a fusion implant insertion location in a sacroiliac joint, theabrading device comprising: an abrading head at a distal end of theabrading device, the abrading head having: abrading surfaces on each ofa first pair of opposing sides, the abrading surfaces comprising one ormore teeth, barbs, blades, ridges, slots, broaches, or other memberscapable of abrading a cortical bone of the sacroiliac joint; and an opentip comprising a cutting edge disposed at a leading edge of the opentip, the cutting edge configured to cut bone tissue in the sacroiliacjoint; and a slide hammer assembly at a proximal end of the abradingdevice, the slide hammer assembly having a released position thatenables operation of the slide hammer assembly, a locked position thatprohibits operation of the slide hammer assembly, and a releasing meansfor transitioning the slide hammer assembly between the locked positionand the released position.
 10. The multimodal abrading device of claim9, wherein each side of the first pair of opposing sides is asubstantially planar member having a distal edge terminating at the opentip, an interface between the open tip and the distal edge comprising asubstantially straight cutting edge.
 11. The multimodal abrading deviceof claim 10, wherein the abrading head further comprises a void and asecond pair of opposing sides, each side of the second pair of opposingsides comprising a curved distal portion terminating at the open tip,the interface between the open tip and the curved distal portioncomprising a curved cutting edge.
 12. The multimodal abrading device ofclaim 11, wherein the curved distal portion of each side of the secondpair of opposing sides comprises a taper toward its opposite side of thesecond pair.
 13. The multimodal abrading device of claim 9, wherein theslide hammer assembly further comprises: a collar on the abradingdevice, the collar having internal threads and external threads; a slidehammer shaft having a threaded end for mating with the internal threadsof the collar on the abrading device, and having a slide stop endopposite from the threaded end; and a hammer sleeve having a hollow,cylindrical bore comprising an internal diaphragm and a threadedconnector configured for mating with the external threads of the collarsuch that when mated the hammer sleeve is engaged in the lockedposition, the diaphragm having a diaphragm opening sized to permitsliding passage of the slide hammer shaft and block passage of the slidestop end.
 14. The multimodal abrading device of claim 13, wherein theabrading head further comprises a void and a second pair of opposingsides, each of the second pair of opposing sides having an opening forenabling lateral ingress into and egress from the void.
 15. Themultimodal abrading device of claim 13, wherein each side of the firstpair of opposing sides is a substantially planar member having a distaledge terminating at the open tip, an interface between the open tip andthe distal edge comprising a substantially straight cutting edge. 16.The multimodal abrading device of claim 13, wherein the abrading headfurther comprises a void and a second pair of opposing sides, each sideof the second pair of opposing sides comprising a curved distal portionterminating at the open tip, an interface between the open tip and thecurved distal portion comprising a curved cutting edge.
 17. Themultimodal abrading device of claim 14, wherein each side of the firstpair of opposing sides is a substantially planar member having a distaledge terminating at the open tip, an interface between the open tip andthe distal edge comprising a substantially straight cutting edge. 18.The multimodal abrading device of claim 17, wherein each side of thesecond pair of opposing sides comprises a curved distal portionterminating at the open tip, the interface between the open tip and thecurved distal portion comprising a curved cutting edge.
 19. Themultimodal abrading device of claim 16, wherein the curved distalportion of each side of the second pair of opposing sides comprises ataper toward its opposite side of the second pair.
 20. The multimodalabrading device of claim 19, wherein each side of the first pair ofopposing sides is a substantially planar member having a distal edgeterminating at the open tip, an interface between the open tip and thedistal edge comprising a substantially straight cutting edge.